IR-aware sneak routing

Abstract

A method for routing a circuit device having an array of bump pads includes identifying a routing direction associated with a bump, generating a power strap and a ground strap based on the routing direction, forming a routing channel in accordance with the routing direction, setting a start point and an endpoint in the routing channel, and connecting the start point and the endpoint using a wire within the routing channel. The method further includes placing the start point to a power or ground strap in response to a target power/ground ratio.

What is claimed is: 
     
       1. A computer-implemented method for routing a flip-chip circuit device having an array of bumps, the computer-implemented method comprising:
 identifying, using the computer, a routing direction associated with a bump included in the flip-chip circuit device when the computer is invoked to identify the routing direction; 
 forming, using the computer, a routing channel in accordance with the routing direction; 
 setting, using the computer, a start point and an endpoint in the routing channel; and 
 connecting, using the computer, the start point and the endpoint using a wire. 
 
     
     
       2. The computer-implemented method of  claim 1 , wherein identifying the routing direction is based on one or more pre-routed nets associated with the bump. 
     
     
       3. The computer-implemented method of  claim 1 , wherein forming the routing channel comprises:
 setting a boundary around the center of the bump; 
 extending the boundary lengthwise in the routing direction; 
 determining whether the boundary is extendable in the routing direction; 
 if the boundary is extendable in the routing direction: 
 extending the boundary until it contacts a power/ground (P/G) bump, a P/G strap, or a barrier; and 
 if the boundary is not extendable in the routing direction: 
 terminating the boundary extension. 
 
     
     
       4. The computer-implemented method of  claim 3 , further comprising:
 extending the boundary widthwise in a direction orthogonal to the routing direction until the boundary reaches the center of adjacent bumps arranged lengthwise in the routing direction. 
 
     
     
       5. The computer-implemented method of  claim 4 , wherein the boundary straddles two adjacent P/G straps. 
     
     
       6. The computer-implemented method of  claim 5 , further comprising:
 calculating a routing area within the boundary, the routing area having a first edge and a second edge opposite the first edge in the routing direction, the first edge associated with the start point and the second edge associated with the endpoint. 
 
     
     
       7. The computer-implemented method of  claim 6 , wherein the endpoint is located at the center of the second edge, and the wire interconnecting the start point and the endpoint comprises a plurality of partially overlapped segments, each of the overlapped segments having a regularly polygonal shape. 
     
     
       8. The computer-implemented method of  claim 7 , wherein the regularly polygonal shape is a rectangle or an octagon. 
     
     
       9. The computer-implemented method of  claim 5 , wherein the start point is electrically connected to a power strap or a ground strap in response to a target power/ground ratio. 
     
     
       10. The computer-implemented method of  claim 1 , further comprising:
 sneaking the wire around bumps in the routing channel. 
 
     
     
       11. A non-transitory computer readable medium comprising instructions which when executed by a computer cause the computer to:
 identify a routing direction associated with a bump pad included in a flip-chip design when the computer is invoked to identify the routing direction; 
 form a routing channel in accordance with the routing direction; 
 set a start point and an endpoint in the routing channel; and 
 connect the start point and the endpoint using a wire within the routing channel. 
 
     
     
       12. The non-transitory computer readable medium of  claim 11 , wherein the routing direction is identified based on one or more pre-routed nets associated with the bump pad. 
     
     
       13. The non-transitory computer readable medium of  claim 11 , wherein the instructions that cause the computer to form the routing channel further cause the computer to:
 set a boundary around the center of the bump pad; 
 extend the boundary lengthwise in the routing direction; 
 determine whether the boundary is extendable in the routing direction; 
 if the boundary is extendable in the routing direction: 
 extend the boundary until the boundary is in contact with a power/ground (P/G) bump pad, a P/G strap, or a barrier; and 
 if the boundary is not extendable in the routing direction: 
 terminate the boundary extension. 
 
     
     
       14. The non-transitory computer readable medium of  claim 13 , further comprising instructions that cause the computer to:
 extend the boundary widthwise in a direction orthogonal to the routing direction until the boundary reaches the center of adjacent bump pads arranged lengthwise in the routing direction, wherein the boundary straddles two adjacent P/G straps. 
 
     
     
       15. The non-transitory computer readable medium of  claim 14 , further comprising instructions that cause the computer to:
 calculate a routing area within the boundary, wherein: 
 the routing area comprises a first edge and a second edge opposite the first edge in the routing direction, the first edge associated with the start point and the second edge associated with the endpoint; 
 the endpoint is located at the center of the second edge, and 
 the wire interconnecting the start point and the endpoint comprises a plurality of partially overlapped segments, each of the overlapped segments having a regularly polygonal shape. 
 
     
     
       16. The non-transitory computer readable medium of  claim 11 , further comprising instructions that cause the computer to:
 sneak the wire around bump pads in the routing channel. 
 
     
     
       17. A system for routing a flip-chip circuit having an array of bump pads, the system comprising:
 at least one processing unit configured to: 
 identify a routing direction associated with a bump pad included in the flip-chip circuit, when the system is invoked to identify the routing direction; 
 form a routing channel in response to the routing direction; 
 set a start point and an endpoint in the routing channel; and 
 connect the start point and the endpoint using a wire within the routing channel. 
 
     
     
       18. The system of  claim 17 , wherein the routing channel has a rectangular shape straddling a power strap and a ground strap. 
     
     
       19. The system of  claim 18 , wherein the start point is electrically connected to the power strap or the ground strap in response to a target power/ground ratio. 
     
     
       20. The system of  claim 19 , wherein the power trap or the ground trap is associated with a respective core power bump or a core ground bump, and the at least one processing unit is further configured to:
 sneak the wire around bumps in the routing channel along the routing direction toward an I/O region. 
 
     
     
       21. The system of  claim 17 , wherein the at least one processing unit is further configured to:
 calculate a routing area with the routing channel. 
 
     
     
       22. The system of  claim 21 , wherein the routing area comprises:
 a first edge associated with the start point; 
 a second edge opposite the first edge in the routing direction and associated with the endpoint; 
 the endpoint located at the center of the second edge; and 
 the wire interconnecting the start point and the endpoint comprising a plurality of partially overlapped segments. 
 
     
     
       23. The system of  claim 22 , wherein each of the overlapped segments comprises a regularly polygonal shape. 
     
     
       24. The system of  claim 23 , wherein the regularly polygonal shape is a rectangle or an octagon.